1. Field of the Invention
This invention relates to the field of structural members. More particularly, this invention relates to the field of articulated interlocking structural extrusions for recreational vehicles and the like.
2. Description of Related Art
Structural members made of lightweight materials such as aluminum are well known. Extrusions made from aluminum are popular for use in applications in which structural members must be strong but lightweight.
In recreational vehicles such as motor homes, the need is particularly acute for strong structural members. Both towed and self propelled recreational vehicles experience vibration on the road and around curves, jars and jolts over bumps and potholes, and experience high winds associated with highway travel, sometimes into a strong headwind which greatly increases the wind speed experienced by the structure. Each structural member of a recreational vehicle must therefore not only strong by itself, but the assembled structure as a whole must be firmly and strongly held together. At the same time, the structural members in recreational vehicles must be lightweight for reasons of fuel efficiency, vehicle stability, and tire wear. For these reasons, extruded aluminum structural members have been used by some recreational vehicle manufacturers as preferred structural members.
Another requirement of the recreational vehicle industry is that the structure be easily assembled. U.S. Pat. No. 5,218,792 issued to Cooper shows a housing structure for use in recreational vehicles which uses aluminum extrusions having a honeycomb structure for strength. The aluminum extrusions are riveted together. U.S. Pat. No. 5,553,906 issued to Kunz shows extruded aluminum floors and sidewall members, and discloses a method of joining those members together which relies on sets of complementary sets of teeth to interlock those members together.